Hermetically sealed secondary battery with lanthanum nickel anode

ABSTRACT

A hermetically sealed secondary battery has at least one solid cathode, at least one hydrogen gas diffusion anode of lanthanum nickel spaced from the cathode, and an alkaline electrolyte in contact with the cathode and anode. Such a battery provides a light-weight, high-power output device.

United States Patent 1 Will [451 Apr. 1,1975

[ HERMETICALLY SEALED SECONDARY BATTERY WITH LANTHANUM NICKEL ANODE [75] Inventor: Fritz G. Will, Scotia. NY.

[73] Assignee: General Electric Company,

Schenectady. NY.

[22] Filed: June 29, 1973 [2]] Appl. No.: 374,907

[52] U.S. Cl 136/6 R. l36/20. l36/28 [51] int. Cl. l-l0lm 35/02 [58] Field of Search l36/28-29. 136/20. I20, I20 FC. 6 R. 137. 83 R. 86 D.

86 DD. I00 R [56] References Cited UNITED STATES PATENTS 3.311.502 3/l967 Dryden 136/28 3.401008 lO/ i968 3.692.584 9/]972 Dilworth ct a] l36/l20 FC X King l36/83 R Primary Eraminer-Anthony Skapars Attorney. Agent, or Firm-Paul R. Webb. ll; Joseph T. Cohen; Jerome C. Squillaro [57] ABSTRACT A hermetically sealed secondary battery has at least one solid cathode. at least one hydrogen gas diffusion anode of lanthanum nickel spaced from the cathode. and an alkaline electrolyte in contact with the cathode and anode. Such a battery provides a light-weight. high-power output device.

4 Claims, 1 Drawing Figure HERMETICALLY SEALED SECONDARY BATTERY WITH LANTHANL'M NICKEL ANODE This invention relates to secondary batteries and. more particularly. to secondary batteries in which a solid cathode and a hydrogen gas diffusion anode of lanthanum nickel are in contact with an alkaline elec trolyte.

Hcrmetically sealed secondary batteries. which entploy hydrogen gas diffusion electrodes. are desirable as power sources.

In LES. Letters Pat. No. 3.476.607. there is described a deferred action self-timing fuel cell wherein a given amount of hydrogen gas is permitted to diffuse into and become absorbed in the hydrogen electrode. preferably palladium. Since the hydrogen electrode is sealed from the external environment. no gas exists above or adjacent to the hydrogen electrode. This quantity of gas accordingly is rate controlling and the device is so de signed that it will fail as soon as the hydrogen gas supply absorbed in the hydrogen electrode is depleted Such a time span can be of the order of say 2 to (i seeonds. The zone or chamber adjacent to the other or re ducing electrode. c.g.. the oxygen chamber. can be sealed or open. and a captive or sealed source of oxi- LllYLt. which can he in solid or fluid form. preferably a sealed source of oxygen. cg. contained in a fracturable container or vial. may he provided to such reducing electrode by breaking or fracturing the vial with the oxidi7cr. c.g.. oxygen. flowing or diffusing to the electrode surface.

British Pat. No. S'lbl/l 88] describes a secondary battery with lead plates and an exciting liquid which is assumed to be sulfuric acid. Upon charging the positive electrode disengages hydrogen which is carried to the negative electrode. The negative electrode disengages oxygen which stores itself as the positive electrode. When the battery is charged the negative plate is situated above its corresponding positive plate. During discharge the battery is inverted.

My present invention is directed to a unique secondary battery employing a solid cathode and a gas diffusion anode of lanthanum nickel which battery has a theoretical energy density comparable to commerual nickel-cadmium batteries.

It is a primary object of my invention to provide a light-weight. highpower output battery.

In accordance with my invention. a hermetically sealed secondary battery has a casing. at least one solid cathode positioned within the casing. at least one hydrogen gas diffusion anode of lanthanum nickel posi tioned within the casing and spaced from the cathode. and an aqueous alkaline electrolyte in contact with both the cathode and the anode.

These and various other objects. features and advantages of the invention will be better understood from the following description taken in connection with the accompanying drawing in which:

The single FIGURE is a sectional view of a hermetically sealed secondary battery embodying my invention.

In the single FIGURE of the drawing there is shown generally at 10 a battery embodying my invention. which battery or cell has a casing I! with a body portion [2 having a closed bottom and an open top. and a cover portion [3 fitting tightly over the open top of body portion [2 thereby providing a hermetically sealed casing. ('asing ll defines a chamber I4 in which there is provided an electrolyte l5 of an aqueous alktu line solution such as potassium hydroxide. A metallic oxide positive electrode I6 is positioned within casing II and immersed at least partially in electrolyte solution 15. Electrode if is shown as a nickel hydroxide electrode which has an electrically eonducti\e screen l7 with nickel hydroxide powder 18 sintered thereon. An electrical conductive lead I) is in electrical contact with screen I7 and extends outwardly through an opening in cover portion l3.

A negative electrode 20 is positioned within casing ll. is immersed at least partially in electrolyte solution l5 and is spaced from positive electrode l6. Negative electrode 20 is shown in the form of a solid plate 21 of lanthanum nickel with an electrically conductive lead 22 which lead extends outwardly through an opening in cover portion 13.

I found unexpectedly that I could form a hermetically sealed secondary battery employing lanthanum nickel as the hydrogen gas diffusion electrode which battery provides a theoretical energy density comparable to a standard nickel cadmium battery. The present battery employing a nickel hydroxide cathode and a lanthanum nickel anode has a theoretical density of lllll Wh/lb which compares well with )7 Wh/lb of a standard nickel cadmium battery. My unique battery produces an open circuit voltage of [.3 volts and produces current density up to St) til/C111 I found unexpectedly that lanthanum nickel in various configurations provides a very suitable hydrogen gas diffusionelectrode which can be employed in at hermetically sealed battery. I knew previously of work of others which had shown that some hexagonal intermetallic compounds of the composition AB; where A represents a rare earth metal and B represents nickel co halt can readily absorb and desorb large quantities of hydrogen gas under relatively small pressures at room temperature. Other than the above information relative to such hexagonal intermetallic compounds nothing appeared to be known to others or myself about the catalytic properties of this class of compounds. Furthermore. there was no previous information of which I was aware that an electrode could be made of such material and secondly that such an electrode could be employed as a hydrogen gas diffusion electrode in an electrolyte solution.

I found that lanthanum nickel exhibited considerable catalytic activity with respect to hydrogen. I found further that it was suitable for use as an electrode in electrochemical devices such as batteries and fuel cells. I discovered further that lanthanum nickel as the anode could be employed in a battery and coupled with a varicty of common commerical cathodes to result in useful batteries. I found in particular that cathodes of nickel hydroxide, silver oxide. or manganese dioxide could be coupled with the lanthanum nickel for suitable use in batteries. I found further that the potential of a charged lanthanum nickel electrode is close to that of a reversible hydrogen electrode. Thus, I was able to form a battery with a lanthanum nickel anode. an alkaline electrolyte and a cathode such as nickel hydroxide or silver oxide. which battery produced an open circuit voltage of l.3 volts.

In my battery. a lanthanum nickel anode can be employed in various forms. I prepared initially electrodes of lanthanum nickel by melting lanthanum and nickel together in appropriate proportions resulting in suitable electrodes without further treatment The elec' tronic conductivity of this compound. lanthamim nickel. equals that of metals thereby eliminating any problem with respect to making suitable contact between a current collector and electrode. ()thcr configurations could be suitable for such an electrode.

A particularly useful construction of such an anode can be a pocket type plate. Such a plate consists of Ianthanum nickel granules or particles contained in a pocket made of perforated metal or porous plastic. Such a construction with the desirable elestic properties in the pocket would allow for expansion and contraction of the lanthanum nickel as it absorbs and desorbs hydrogen while simultaneously assuring good physical contact between indi idual lanthanum nickel particles. This pocket type plate will also prevent loss of material due to flufting during charge and discharge which has been experienced with a bulk piece of Ian thanuni nickel as the anode.

Various common commercial cathodes such as nickel hydroxide. silver oxide or manganese dioxide can be employed with the lanthanum nickel anode in an alkaline solution. Various alkaline electrolytes, which are aqueous alkali solutions of any desired coir centration. may be used. such as potassium hydroxide or sodium hydroxidev I avoid acid electrolyte solutions since considerable corrosion has been observed em ploying such acid electrolytes.

l found further that the ampere hour capacity and hence the energy density of batteries employing my inrention including lanthanum nickel as the anode depends upon the capacity ofthc lanthanum nickel anode to absorb hydrogen. One mol of nickel in lanthanum nickel can absorb up to (1.7 mols of hydrogen. From this data theoretical energy density of my lanthanum nickel-nickel hydroxide battery has been calculated at ltltl Wh/lb. I found further that at elevated temperatures less hydrogen can be absorbed at one atmosphere pressure than at room temperature and consequently the ampere-hour capacity of the electrode decreases In a hermetically sealed battery hydrogen pressure builds up in the battery as the temperature increases.

During charging of the hermetically sealed battery of my present invention. water is discharged on the lanthanum nickel electrode to yield hydroxyl ions and hydrogen is absorbed between electrodes. On discharge of my battery the opposite reaction takes place wherein hydrogen combines with the hydroxyl ions to form water. Examples of batteries made in accordance with my Ill invention are set forth below:

FXAMPLF. l

A \ented battery was prepared by employing a suitable casing of polypropylene in which was fitted a pair ofspaced apart electrodes. The anode as made of lanthamim nickel and had a current collector lead. The anode was prepared by melting together lanthanum and nickel in appropriate proportions of [.aNi- The nickel hydroxide cathode was a conventional commer cial cathode which had a current collector lead. (\N potassium hydroxide was employed as the electrolyte which was contained within the battery container and in contact with both of the spaced apart electrodes. The resulting de\ ice as a rented battery with a lanthanum nickel anode made in accordance with my in en' tion.

EXAMPLE ll The rented battery of Example I produced an open circuit voltage of L3 volts and current densities up to 50 ma/cm. Further. at 25 mil/CD1 2! polarization of approximately Ktltl inv was observed on charge as well as discharge.

While other modifications ofthe invention and variations thereof which may be employed within the scope ofthe invention have not been described. the invention is intended to include such as may be embraced within the following claims:

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A hermetically sealed secondary battery compris ing a casing. at least one solid cathode positioned within the casing. at least one hydrogen gas diffusion anode of lanthanum nickel positioned within the casing and spaced from the cathode. and an aqueous alkaline electrolyte in contact with both the cathode and the anode.

2. A hermetically sealed secondary battery as in claim I. in which the cathode is nickel hydroxide, and the electrolyte is potassium hydroxide.

3. A hermetically sealed secondary battery as in claim I, in which the lanthanum nickel anode is an alloy plate.

4. A hermetically sealed secondary battery as in claim I, in which the lanthanum nickel anode consists of a perforated container. and a plurality of lanthanum nickel particles therein 

1. A HERMETICALLY SEALED SECONDARY BATTERY COMPRISING A CASING, AT LEAST ONE SOLID CATHODE POSITIONED WITHIN THE CASING, AT LEAST ONE HYDROGEN GAS DIFFUSION ANODE OF LANTHANUM NICKEL POSITIONED WITHIN THE CASING AND SPACED FROM THE CATHODE, AND
 2. A hermetically sealed secondary battery as in claim 1, in which the cathode is nickel hydroxidE, and the electrolyte is potassium hydroxide.
 3. A hermetically sealed secondary battery as in claim 1, in which the lanthanum nickel anode is an alloy plate.
 4. A hermetically sealed secondary battery as in claim 1, in which the lanthanum nickel anode consists of a perforated container, and a plurality of lanthanum nickel particles therein. 